Morgan hit back on Twitter and accused McGregor of throwing a "thespian tantrum".

He tweeted: "Sorry to hear that @mcgregor_ewan - you should be big enough to allow people different political opinions. You're just an actor after all.

"A real man would have come on and debated it with me, not run away like a coward.

"I'll be writing a column about @mcgregor_ewan today, once I have sent it to him for his approval."

He then tweeted simply: "Vainspotting."

More than five million people took part in protests across the globe on Saturday against the US President's agenda and rhetoric.

:: Millions of women protest against Trump worldwide

In the United States, organisers said one million demonstrators took part in the Women's March on Washington to express their concerns that women's rights will be eroded under the billionaire's presidency.

More than 600 "sister marches" were held in conjunction with the Washington event around the world - including in Sydney, London and other major US cities including Chicago, Atlanta and New York.

:: Madonna defends blow up White House 'metaphor' at Trump march

Among the famous faces in the crowds were actors Charlize Theron, Scarlett Johansson, Jake Gyllenhaal, Emma Watson, America Ferrera and Ashley Judd, as well as singers Madonna, Katy Perry and Cher.